Hydrogen production system and method for producing hydrogen in a hydrogen production system

Abstract

Provided is a hydrogen production system including a thermal energy storage having a housing, a storage chamber with heat storage material inside the storage chamber and a fluid inlet port fluidically connected to the storage chamber and a fluid outlet port fluidically connected to the storage chamber, and at least one high temperature electrolyser for producing hydrogen, whereby the at least one high temperature electrolyser is thermally connected to the heat storage material of the storage chamber of the thermal energy storage. Several modes of operation are defined. A method for producing hydrogen in the hydrogen production system is also provided.

1 . A hydrogen production system comprising a thermal energy storage having a housing, a storage chamber with heat storage material inside the storage chamber and a fluid inlet port fluidically connected to the storage chamber and a fluid outlet port fluidically connected to the storage chamber, and at least one high temperature electrolyser for producing hydrogen, wherein the at least one high temperature electrolyser is thermally connected to the heat storage material of the storage chamber of the thermal energy storage, wherein the fluid inlet port and/or the fluid outlet port of the thermal energy storage are thermally connected to an electric heater,
 and wherein a control unit is coupled to the hydrogen production system, wherein the control unit is configured to operate the hydrogen production system in
 a first mode, in which electrical energy is supplied to the electric heater, wherein it is converted to thermal energy, wherein the thermal energy is transferred to the high temperature electrolyser, in which hydrogen is produced, 
 a second mode, in which electrical energy is supplied to the electric heater, wherein it is converted to thermal energy, wherein the thermal energy is transferred to the thermal energy storage, in which it is stored, 
 a third mode, in which no electrical energy is supplied to the electric heater but thermal energy from the thermal energy storage is transferred to the high temperature electrolyser, in which hydrogen is produced, and 
 a fourth mode, in which neither electrical energy is supplied to the electric heater nor thermal energy is transferred to the thermal energy storage. 
   
     
     
         2 . The hydrogen production system according to  claim 1 , wherein,
 the thermal energy storage is a sensible heat storage, a latent heat storage or a thermo-chemical heat storage.   
     
     
         3 . The hydrogen production system according to  claim 1 ,
 wherein   the heat storage material comprises sand and/or stones.   
     
     
         4 . The hydrogen production system according to
   claim 1 , wherein   the heat storage material forms a tunnel system of heat exchange channels within the storage chamber.   
     
     
         5 . The hydrogen production system according to  claim 1 ,
 wherein   the electric heater is electrically connected to a renewable energy source.   
     
     
         6 . The hydrogen production system according to  claim 1 ,
 wherein   the control unit is further configured to operate the hydrogen production system so that:   (a) in the first and/or the second mode, charging mode working fluid is heated in a charging mode, so that a heated charging mode working fluid is obtained, and the heated charging mode working fluid is transported to the fluid inlet port of the thermal energy storage, wherein thermal energy from the heated charging mode working fluid is transferred to the heat storage material of the storage chamber, so that stored thermal energy is stored in the heat storage material,   (b) in the third and/or fourth mode, discharging mode working fluid of a discharging mode is transported to the fluid inlet port of the thermal energy storage, wherein the stored thermal energy from the heat storage material of the storage chamber is transferred to the discharging mode working fluid, so that a heated discharging mode working fluid is obtained, which exits the fluid outlet port of the thermal energy storage and the heat from the heated discharging mode working fluid is thermally transferred to the at least one high temperature electrolyser, wherein hydrogen is produced in the at least one high temperature electrolyser by using the heat from the heated discharging mode working fluid.   
     
     
         7 . The hydrogen production system according to  claim 1 ,
 wherein,   the at least one high temperature electrolyser is thermally connected to the heat storage material of the storage chamber of the thermal energy storage by means of a heat exchanger.   
     
     
         8 . The hydrogen production system according to  claim 1 ,
 wherein,   at least two high temperature electrolysers of the at least one high temperature electrolyser are fluidically connected in series to each other.   
     
     
         9 . The hydrogen production system according to  claim 1 ,
 wherein,   a turbine is connected to the at least one high temperature electrolyser, wherein the turbine is connected to a generator.   
     
     
         10 . The hydrogen production system according to  claim 9 , wherein
 the turbine and the at least one high temperature electrolyser fluidically connected in parallel to each other.   
     
     
         11 . The hydrogen production system according to  claim 1 ,
 wherein,   the at least one high temperature electrolyser is connected via at least one hydrogen line to a hydrogen storage, a polymer electrolyte membrane fuel cell, a solid oxide fuel cell, a combustion chamber, an ammonia synthesis device, a methanation device and/or a hydrogen infrastructure.   
     
     
         12 . The hydrogen production system according to  claim 11 ,
 wherein,   the combustion chamber is connected to a turbine, wherein the turbine is connected to a generator and the turbine is thermally connected to the fluid inlet port.   
     
     
         13 . A method for producing hydrogen in the hydrogen production system according to  claim 1 , wherein the method comprises the steps of:
 (a) heating a charging mode working fluid in a charging mode, so that a heated charging mode working fluid is obtained,   (b) transporting the heated charging mode working fluid to the fluid inlet port of the thermal energy storage, wherein thermal energy from the heated charging mode working fluid is transferred to the heat storage material of the storage chamber so that stored thermal energy is stored in the heat storage material,   (c) transporting discharging mode working fluid of a discharging mode to the fluid inlet port of the thermal energy storage, wherein the stored thermal energy from the heat storage material of the storage chamber is transferred to the discharging mode working fluid, so that a heated discharging mode working fluid is obtained, which exits the fluid outlet port of the thermal energy storage and the heat from the heated discharging mode working fluid is thermally transferred to the at least one high temperature electrolyser,   (d) producing hydrogen in the at least one high temperature electrolyser by using the heat from the heated discharging mode working fluid.   
     
     
         14 . The method for producing hydrogen in the hydrogen production system according to  claim 13 ,
 wherein,   the heat from the heated discharging mode working fluid is transferred to the at least one high temperature electrolyser when a capacity of thermal energy of the storage chamber is at a defined threshold or production of hydrogen is demanded.   
     
     
         15 . The method for producing hydrogen in the hydrogen production system according to  claim 13 ,
 wherein,   the at least one thermal energy storage is connected to a renewable energy source and heat from the heated discharging mode working fluid is transferred to the at least one high temperature electrolyser so that a constant hydrogen production level of the at least one high temperature electrolyser is maintained.